A cellular communication system is a wireless communication network in which geographical areas are divided into a number of smaller areas or cells in order to provide scalability of coverage for multiple users with minimal intercell interference. A mobile cellular communication system is a cellular communication network in which the terminal devices (users, mobiles) may be in motion from one location to another relative to a basestation.
In a typical digital wireless communication system, multiple basestations are provided to perform switching and connection services between users or terminal devices. FIG. 1 illustrates typical cellular wireless communication system architecture. Basestation 105-1 provides wireless communication system to mobile stations 101 and 103. Similarly, basestation 105-2 provides wireless communication system to mobile stations 111 and 113. Basestation 105-1 is connected to the basestation 105-2 via network 107.
Referring to FIG. 1, a basestation (BS) provides basic connection service to terminal devices by terminating the radio path and connecting the terminal devices to network 107. A mobile station (MS) terminates the radio path on the user side and enables the user to gain access to services from the network. Network 107 typically comprises a mobile switching center (MSC). The MSC is an automatic system that interfaces the user traffic from the wireless network with the wireline network or other wireless networks. The basestations exchange messages with the MSC.
A variety of communication protocols can be used to operate and control a wireless communication system such as the system shown in FIG. 1. Representative protocols include, but are not limited to, the TDMA (time division multiple access) and CDMA (code division multiple access) protocol families. Among other adoptions, TDMA protocol is used by GSM (Global System for Mobile Communication) which comprises GPRS (General Packet Radio Service), ECSD (Enhanced Circuit Switched Data), and EDGE (Enhanced Data rates for Global Evolution) systems. The CDMA protocol is adopted by cdma2000, wideband CDMA (WCDMA), IS-95 CDMA, IS-95B CDMA, CDMA TIA IS2000, TIA IS 2000A, WIMS W-CDMA, ARIB WCDMA, 1Xtrem, 3GPP-FDD, 3GPP-TDD, TD/SCDMA, as well as several other multi-carrier CDMA systems. Additional 2G and/or 3G CDMA protocols may be found in WDCDMA for UMTS, Holma and Toskala eds., John Wiley & Sons. Inc., New York, (2000); and IS-95 CDMA and cdma2000, Garg ed., Prentice Hall PTR, Upper Saddle River, N.J., (2000).
Although TDMA and CDMA are the most widely used communication protocols, they each have unique system requirements. Prior art communication systems dedicated to supporting TDMA or CDMA protocols exist. However, the prior art has failed to provide a communication system that is capable of supporting several different protocols, including both TDMA and CDMA, in a satisfactory manner. This failure is in part due to the fact that the hardware necessary to support TDMA is typically not compatible with the hardware necessary to support CDMA. For example, typical TDMA systems require maximum likelihood sequence estimation (MLSE) equalization whereas CDMA systems do not. In contrast, typical CDMA systems require RAKE receivers whereas TDMA systems do not.
Even within the same protocol family, there are variations in the hardware necessary to support the protocol. For example, although both the global positioning system (GPS) and IS-95 are CDMA protocols, GPS and IS-95 have distinctly different hardware requirements. For example, an IS-95 system requires a convolutional decoder whereas GPS does not.
Because of the unique hardware requirements necessary to support each of the existing communication protocols, substantial expense is required to modify a basestation so that it supports a new communication protocol. Indeed, such a modification requires a complete or partial overhaul of a basestation. In prior art systems, the modification of a basestation to support a new communication protocol requires the installation of new equipment as well as significant modification of existing software throughout the network. In addition, new terminal devices are required in order to be compatible with the modified basestation. Thus, modification of a communication protocol used by a basestation 105 is an expensive and time-consuming task that results in service interruptions. For these reasons, conventional wireless communication systems suffer from a lack of flexibility and adaptability, and cannot provide timely and efficient adaptation to meet the ever-changing needs of the wireless communication field.
Further, in conventional wireless communication systems, preparing an application program to run a particular communication protocol requires a programmer to know or understand the complex details and specifics of the underlying communication hardware. Thus, every time there is a change in communication protocol, the programmer has to first understand what changes are to be made at the hardware level and rewrite application programs accordingly. Such dependence on specific architecture of the underlying hardware makes it even more difficult and expensive to change and maintain wireless communication systems.
In view of the foregoing, it is highly desirable to provide an adaptable and flexible wireless communication system. Also, it is desirable to provide a hardware architecture-independent communication platform on which a programmer can write application programs capable of modifying the communication protocol used by a reconfigurable wireless network communication apparatus without understanding underlying hardware requirements necessary to affect such a modification.